July 5, 2000 study--Relationship between Memnoniella & Stachybotrys

[Guest guest]

Phylogenetic Relationships

of Memnoniella and Stachybotrys Species and Evaluation of Morphological

Features for Memnoniella Species Identification

A. Haugland, J. Vesper and M. Harmon

Mycologia, Vol. 93, No. 1 (Jan. - Feb., 2001), pp. 54-65

(article consists of 12 pages)

Published by: Mycological Society of America

Stable URL: http://www.jstor.org/stable/3761605

Abstract

Members of the anamorphic fungal genus Memnoniella

demonstrate morphological and biological similarities to species within

the genus Stachybotrys, and the taxonomic distinctions between the

genera have been the subject of controversy in the past. Sixteen

strains representing described species of Memnoniella were examined for

morphology using light and scanning electron microscopy and for

phylogenetic relationships using comparative sequence analysis of a

segment of the nuclear ribosomal RNA gene operon (rDNA) including the

internal transcribed spacer 1 and 2 regions (ITS1 and ITS2) and 5.8S

gene. These analyses resolved the Memnoniella strains into two highly

divergent phylogenetic clades with morphologies generally consistent

with the current descriptions of M. echinata and M. subsimplex. One

strain, showing morphological features more similar to M. subsimplex,

was placed in the M. echinata clade in the phylogenetic analysis and

probably represents a new species. A second strain, showing a typical

M. echinata DNA sequence, showed morphological features that were

similar to Stachybotrys species when grown on certain culture media.

The evolutionary relationships between the genera were evaluated by

phylogenetic analyses of sequence data from the 18S, 28S, 5.8S rDNA

genes and ITS1 and ITS2 regions. Results of several different analyses

were in agreement in indicating that Memnoniella is paraphyletic to

Stachybotrys.

(Have to login to JSTOR for full report)